Is there anything useful right now, today..... that can be done with an always on 50uN of thrust in space?

Why limit oneself to just one EM Drive engine in space?. How about posing the question as:

Is there anything useful right now, today..... that can be done with an always on N*50uN of thrust in space where N is an integer multiple (1,2,3,4,...) of 50 watts per engine.

For example, 4 engines: total thrust 200uN at total power 200 Watts, 10 engines 500 uN at 500 Watts total.

IIRC, the ISS has 30KWe extra to play with.

That's 600 EM Drives giving 0.03 Newtons total thrust

They need to increase the Thrust/Power to decrease the number of EM Drives necessary.

If the experimental results hold and this thrust is real, it is very low. Before anyone can increase the thrust/power, someone will have to develop a theory that actually explains what is going on. Only then can the process be improved.

It is similar to work in high temperature superconductors. For years chemists have developed new high temperature superconductors with various properties pretty much by trial and error. They also need a working theory.

Once a functional theory is confirmed, one can predict the properties via math and have better results.

We are on the edge of a golden age of spaceflight with EM drives and superconducting capacitors. Or maybe not, but at least it is fun to discuss it.

1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?

Attached is the best I can do on short notice. I've looked at the available color palates in HDFView and they are weak, to say the least. Or maybe I just don't know how to scale them. I would like to know paraview better because I think it could display the data and in the format you wanted. Lines of constant value would be good. iso - whatevers.

So blue is the most negative and red is the most positive in that scale.

What is white ?What is black?

White may be the most positive (off-scale) and black the most negative (off-scale), but I would like you to confirm...

1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?

Attached is the best I can do on short notice. I've looked at the available color palates in HDFView and they are weak, to say the least. Or maybe I just don't know how to scale them. I would like to know paraview better because I think it could display the data and in the format you wanted. Lines of constant value would be good. iso - whatevers.

Hopefully this will be more usable

Quote

What is white ? What is black?

White may be the most positive (off-scale) and black the most negative (off-scale), but I would like you to confirm...

I don't know the answer to your question but I think that your guess is right. I know that the black boarders of the cavity are perfect metal which is confusing as it is not field strength. But the colors are not single valued. The palates seem to be designed for "Pretty" and not for information. There are two single valued palates in hdfview, both gray and both wash out the differences in field strength. The h5topng color palates also wash out the color, and don't even show the evanescent waves. So I'm not using that program. Again, I need to explore paraview's capabilities.

... Just as a note, we've already tried re-enforcing the frustum endplates with angle aluminum mounted on their outside surfaces and we didn't notice any marked change in its thrust response. ...

This was expected not to make any significant difference.

As I wrote in my report:

Quote from: Dr. J. Rodal

Cotterell and Parkes (based on Cotterell's Ph.D. thesis at the University of Cambridge) correctly point out that the distribution of the heat flux "is not significant in the problem" of thermal buckling of a circular plate, whether the heating takes place uniformly over the whole circular plate or is concentrated in a central region. Cotterell chose a distribution with a heatedDiameterRatio =1/0.3=3.333 instead of the heatedDiameterRatio=1 analyzed by Noda et.al. The fact that the exact distribution is not significant for the deltaT that will produce buckling or for the buckling displacement follows from equilibrium: the membrane stress (=E*alpha*deltaT) force resultant (the integral of the membrane stress through the thickness) is reacted at the simply supported edges (that constrain the in-plane displacement). The membrane force resultant is uniform and it is equal in the polar radial and angular (azimuthal) directions. If only a central area is heated, the membrane stress is still equilibrated throughout. If the plate has uniform thickness and isotropic material properties, the strain in the non heated area prior to buckling is the same as in the heated area.

1) The IR measurement was done from the outside, with the IR camera looking at the composite polymer surface of the circuit board surface they had on the exterior of the big diameter flat end. Since this composite polymer has much lower thermal conductivity and much lower thermal diffusivity than copper, please take into account that these IR measurements represent a temperature and temperature gradients significantly lower than those present on the inner (copper) surface of the big diameter flat end. In other words, the composite polymer circuit board surface being measured with the IR camera acts like an insulating surface concealing the higher temperature of the inner copper surface. Moreover, due to very low thermal diffusivity of the glass-fiber-reinforced polymer printed circuit board, measurement of its exterior surface presents a considerable time delay of the interior temperature vs. time profile (as it takes time for the heat to conduct through the thickness of the very low diffusivity of the glass-fiber-reinforced polymer printed circuit board).

2) The modulus of elasticity of the glass-fiber-reinforced polymer printed circuit board is much lower than the modulus of elasticity of the copper. The glass-fiber-reinforced polymer printed circuit board has orders of magnitude lower thermal conductivity and thermal diffusivity than the copper. (Comparison noted below).

3) Why not get rid of the fiber-reinforced-polymer printed circuit board and just simply use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration ?

As to your questions, I would need some time to give them the analytical consideration they deserve and to calculate, rather than give you an impulsive, reflexive, answer that may be incorrect.

NOTE: FR-4 is a composite material made with woven fiberglass cloth embedded in an epoxy resin (polymer) matrix. The in-plane Young's modulus of FR4 is 3.0×10^6 psi , about six times smaller than Copper's Young modulus of 17.0×10^6 psi. The modulus of elasticity in the thickness direction is much lower, practically as low as the modulus of elasticity of epoxy. FR4's coefficient of thermal expansion - x-axis 1.4×10^(−5) 1/K, Coefficient of thermal expansion - z-axis 7.0×10^(−5) 1/K

The thermal conductivity is a tiny 0.29 W/m·K in the thickness direction, due to the low thermal conductivity of the epoxy resin. Copper has a thermal conductivity of 401 W/m·K, that is 1400 times higher than the thermal conductivity of FR4

3) Why not get rid of the fiber-reinforced-polymer printed circuit board and just simply use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration ?

Answer: I used the FR4 PCB with 1.0oz copper end-plates to minimize payload mass while maximizing the thrust to weight ratio of the copper frustum assembly AND the signal to noise ratio of the torque pendulum system. I used the 1.0oz copper thickness because the ac skin depth of RF at 1.5 GHz is about 2.0 microns, so 5X that depth or 10 microns of copper should contain 99% of the ac currents at this frequency. And I still had an additional 25 microns of copper thickness as non-current carrying thermal mass to stabilize its performance.

Now if you care to look at my pictures of the large OD end of the Eagleworks copper frustum, the mass of the entire frustum assembly without the PE discs is listed as 1.606 kg. Your 0.25" thick solid copper end plates would add over 3.0 kg of dead mass to this figure just for the small and large OD ends plates and cost us $333.50 for a 12"x 24"x0.25" copper plate stock from McMaster-Carr needed to make them. As I've said before we have tried aluminum angles and even 0.090" thick AL plates across the existing PCB end caps and noticed no change in its performance except for the increase in seismic noise pickup that the extra mass such payload-mass increasing modifications always bring to the table.

...the large OD end of the Eagleworks copper frustum, the mass of the entire frustum assembly without the PE discs is listed as 1.606 kg. Your 0.25" thick solid copper end plates would add over 3.0 kg of dead mass to this figure just for the small and large OD ends plates and cost us $333.50 for a 12"x 24"x0.25" copper plate stock from McMaster-Carr needed to make them.

You don't need to replace both the small and big diameter flat plates. You only need to change the big diameter flat end plate to test whether thermal instability is an artifact in the NASA experiments. The dielectric HD PE shields the small diameter end plate from heating. I understood from prior communication with you that you could have ~ 20 pounds = 9 kg on the platform. If a big diameter 1/4 inch thick copper end plate adds more mass than what your stand can support, you may still be able to test a 1/8 inch thick copper end plate (just for the Big Diameter end plate) as I proposed in my study based on the previous smaller power input. The mass of a 1/8 thick copper end for the big diameter would be 1.74 kg, hence the added mass will be 1 kg (calculating that the mass of the discarded FR4 with copper is ~0.73 kg). As I show in my report, it will significantly increase the time at which any thermal instability can take place, and this would be very noticeably in the experiments. Another benefit of using a 1/8 inch thick copper end plate is that copper has several orders of magnitude greater thermal diffusivity than the FR4 epoxy composite you are using. The FR4 is masking the true temperature profile (vs. time) of the end plate. Eliminating the FR4 would give you a much more realistic temperature and temperature gradient profile vs time.

(The IR measurement was done from the outside, with the IR camera looking at the composite polymer surface of the circuit board surface they had on the exterior of the big diameter flat end. Since this composite polymer has much lower thermal conductivity and much lower thermal diffusivity than copper, please take into account that these IR measurements represent a temperature and temperature gradients significantly lower than those present on the inner (copper) surface of the big diameter flat end. In other words, the composite polymer circuit board surface being measured with the IR camera acts like an insulating surface concealing the higher temperature of the inner copper surface. Moreover, due to very low thermal diffusivity of the glass-fiber-reinforced polymer printed circuit board, measurement of its exterior surface presents a considerable time delay of the interior temperature vs. time profile (as it takes time for the heat to conduct through the thickness of the very low diffusivity of the glass-fiber-reinforced polymer printed circuit board).

FR4 thermal conductivity is a tiny 0.29 W/m·K in the thickness direction, due to the low thermal conductivity of the epoxy resin. Copper has a thermal conductivity of 401 W/m·K, that is 1400 times higher than the thermal conductivity of FR4. )

we have tried aluminum angles and even 0.090" thick AL plates across the existing PCB end caps and noticed no change in its performance except for the increase in seismic noise pickup that the extra mass such payload-mass increasing modifications always bring to the table.

If thermal buckling occurs, it will bend the end plate towards the interior of the EM Drive, the center of the end plate will move towards the inside (not the outside) of the EM Drive (reference: my report). It moves towards the inside because the inside surface of the microwave EM Drive is hotter than the outside surface, hence there is a thermal gradient through the thickness which will bend the surface towards the inside such that the hotter (inner) surface expands more than the cooler (outside) surface. As such, installing aluminum angles or stiffeners on the outside of the big diameter end plate is not going to help, because the thermal buckling deflection will be away from it, not towards it. Even if you would try to install stiffeners on the inside copper surface of the big diameter end plate (which may interfere with the EM Drive electromagnetic field) it would not be a good solution because the buckling deflections are very small (hence the stiffeners would need to be welded or rigidly adhered to the surface of the end plate all across, to make a difference).

1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?

Attached is the best I can do on short notice. I've looked at the available color palates in HDFView and they are weak, to say the least. Or maybe I just don't know how to scale them. I would like to know paraview better because I think it could display the data and in the format you wanted. Lines of constant value would be good. iso - whatevers.

Hopefully this will be more usable

Quote

What is white ? What is black?

White may be the most positive (off-scale) and black the most negative (off-scale), but I would like you to confirm...

I don't know the answer to your question but I think that your guess is right. I know that the black boarders of the cavity are perfect metal which is confusing as it is not field strength. But the colors are not single valued. The palates seem to be designed for "Pretty" and not for information. There are two single valued palates in hdfview, both gray and both wash out the differences in field strength. The h5topng color palates also wash out the color, and don't even show the evanescent waves. So I'm not using that program. Again, I need to explore paraview's capabilities.

If it were easy, everyone would do it, no?

An alternative suggestion is that you could output (from MEEP) numerical values of the evanescent field at chosen locations (for example where you see maxima and minima from the graph, or where you see off-limit values like in the white zones, or at interesting locations, like for example near the corners of the EM Drive) to ascertain what are the contour magnitudes.

I tried to attach the digital output source of the final fields for the copper kettle as designed. It is only 125.4 MB, I would like to share the much more interesting file showing the evolution of the fields from start-up, but it is 4.4 GB so it might not be something Chris would want me to do. Actually, Chris doesn't want people uploading .h5 files at all. I discovered after waiting through the complete upload that .h5 is not an allowed format.

I tried to attach the digital output source of the final fields for the copper kettle as designed. It is only 125.4 MB, I would like to share the much more interesting file showing the evolution of the fields from start-up, but it is 4.4 GB so it might not be something Chris would want me to do. Actually, Chris doesn't want people uploading .h5 files at all. I discovered after waiting through the complete upload that .h5 is not an allowed format.

I was suggesting you to look at a few values, if you had the time and if you were interested on what those contours mean. Otherwise I understand No way I suggested to attach GB-long files.

@Rodal -You have asked to see forces for empty cavities at two frequencies. I am working on it but I need to caution you to not take the results to seriously. If my proposition is right then there are several factors that effect the force values. Remember, I have toyed with forces and the gap locations for some time. I have selected locations that generate the largest forces within the bounds of resolution and meep digitization. I don't know of any reason to think that the experimental thrusters would have accidental gaps allowing RF power to escape the cavity at those exact locations.

I can imagine RF power leaking around the gasket where the end is joined to the cone, and because this leakage is accidental and unmonitored, I seriously doubt that it would be the same two times in a row when the end plate is removed and replaced. It would have been removed and replaced in order to insert the dielectric after measuring no thrust without said dielectric. Well, maybe the gap sizes were different which dramatically alters the force. The smaller the gap, the larger the force detected.

While I was toying with forces in isolation, it was OK for me to put the gaps where I wanted, but now that we are more seriously exploring the concept of evanescent waves related to force, I should step back and approach the model more realistically. By that I mean that I should close the gaps in the base plate and model the gasket between the end plates and the cone body using the data that I now have from Paul March. All I need in order to do that is the dielectric constant of the gasket material, and I expect that is readily available. I already have the gasket modelled as an air or vacuum gap but have not run cases using both gasket gaps simultaneously. I think I should do this so that any answer obtained can be related more directly to the experimental data that we have. I know from previous calculations that the force on the CG of the thruster is very much smaller when simulating gaps on only one end of the thruster ~ O(2-3)/c, that is, only slightly more than a classic photon rocket. I have ran that case for a single gasket gap. Similar results obtain for single end plate gaps though slightly larger.

The other thing that would be most useful would be a verification of the superluminal velocity proposition of evanescent waves. If that proposition could be mathematically confirmed then it might be possible to formulate a closed form (or nearly so) solution to the force generation of EM thrusters. Meep can not do that.

As an aside, another thing I know from prior runs is that the gap close to the corners of the EM thruster causes much greater force to be detected than gaps away from the corners. By corners, I mean the join between the cone body and the base plate. I think that is related to the thought that evanescent waves naturally obtain in the inside corners of the cavity but not in the center of the base plate.

I am proposing then, that I drop this "side" investigation of gaps in the base plate and return to a higher fidelity model of the EM thruster cavity as we now know it.

I would hope that you and Mathematica would pursue the calculation of velocity of the evanescent waves through small gaps. I expect that if you do so, you will obtain numbers that are unbelievably large, O (10^15) more or less. Also, depending on your assumptions, I expect that you will determine that the evanescent wave velocity drops to c or less immediately upon exiting the gap. It would not do for me to run this calculation because this whole idea needs independent verification, but you and Mathematica are totally independent of me and meep, so that should help forward our progress.

If you really need for me to pursue the forces on the empty cavity caused by the base plate gaps, I will do so but recognize in light of the above, that such results will not be meaningfully related to the EM thruster experimental results that we have available.

From what I am reading you keep mentioning "superluminal velocity proposition of evanescent waves". Would I be correct in assuming that you are talking about the apparent velocity of teh wavform themselves and not the matter or energy that the waveforms themselves are composed of?

From what I am reading you keep mentioning "superluminal velocity proposition of evanescent waves". Would I be correct in assuming that you are talking about the apparent velocity of teh wavform themselves and not the matter or energy that the waveforms themselves are composed of?

Otherwise, this put's a whole new slant on this EM drive debate.

I'm referring to superluminal velocity as presented here http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdfI need an interpretation from someone more knowledgeable than I, in order to know exactly what it is that I'm talking about. Perhaps you can tell me?

From what I am reading you keep mentioning "superluminal velocity proposition of evanescent waves". Would I be correct in assuming that you are talking about the apparent velocity of teh wavform themselves and not the matter or energy that the waveforms themselves are composed of?

Otherwise, this put's a whole new slant on this EM drive debate.

I'm referring to superluminal velocity as presented here http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdfI need an interpretation from someone more knowledgeable than I, in order to know exactly what it is that I'm talking about. Perhaps you can tell me?

In this case I wouldn't profess any sort of knowledge. I't's only fairly recently that I've come to accept that Space can expand faster than the velocity of light. Although in retrospect, considering the age of the universe and it's apparent size, the concept is pretty much self evident.

I would speculate that it may be possible that what is being done is inducing a Space/Time wave form that could be transferring momentum to the drive itself by causing a high frequency oscillation of compression and expansion of Space itself. It may be possible that compression and expansion of Space could be induced via electromagnetic frequencies rather than oscillated Strange Matter. In other words, the drive is essentially being dragged along by the expansion of compressed space. Catching the wave as it were.

Mind you, as far as I can tell, this would not violate any currently accepted laws of physics, and Einstein himself even noted that there seems to be a link between gravity and electromagnetism. It's possible that electromagnetism may be able to stretch and compress space in a similar fashion to gravity. The only reason that this hasn't been found out is nobody ever did an experiment quite like this one before.

This is an op ed. Putting this all in perspective, the successful measurement of a thrust signature in hard vacuum helped me gain real confidence that the Emdrive and Cannae* are in fact producing a real thrust signature which begs explanation. For now it appears to work, but barely. Not enough to make people take notice, even though it works >6000x better than a photon rocket. This has potential to be HUGE. It would be irresponsible to not take this seriously now. Yes this is high risk, but it is also very high reward. I've been reading about crowdsourcing science lately after hearing a piece about it on the SGU podcast. Wouldn't it be nice if we could crowdsource research into the Emdrive.

I'm thinking crowdsourcing because there is a taboo associated with this subject. Because it is assumed to go against established scientific concepts. Academic institutions and professionals would no doubt be hesitant to publicly acknowledge involvement in such research, without sufficient evidence this is real. Put another way, they won't touch it until someone before them assumes the risk first. BZ to Eagleworks for having the courage to at least take a look. This is the public attitude, but if you really examine the literature, Emdrive can be explained via established principles and only serves as experimental evidence supporting the quantum foundations of reality.

As I've said, this isn't just some neat thruster, if it works it is also an instrument which could give immense insight into the nature of space and time itself. We really need contributions from experts in optics, materials science and QFT, with open minds. If we go the crowdsource route, we need a platform and we need leadership. Just like the hyperloop. This problem is to be figured out or put to rest. I have confidence that Eagleworks can eventually figure this out, but at the same time, we need to provide forceful backup**. The last thing we need is for this potential world changing technology to fall prey to an unworkable theory which leads to no results and time running out***. I know this sounds harsh, and I mean no disrespect. Do we want to be famous or correct? Both have to be true, to be true. In this writer's opinion, this is exactly what happened to ME. The inability or unwillingness to adapt one's theory in the face of new information and scrutiny. Can you imagine the space flight applications that could come from this potential technology, if it is in fact a reality and we can figure it out? Can you imagine what could have happened if we had not let it slip through the cracks for several more years? We (humanity) need to slough off our scientific hubris. We don't know everything yet; we only think we do. Quoting the controversial Rupert Sheldrake, "The science delusion is the belief that science already understands the nature of reality in principle, leaving only the details to be filled in. This is a very widespread belief in our society........." He is pointing out our hubris, how we think we know it all already, even as we are such a young, immature species. We don't know jack. Our collective ego surpasses our wisdom. The insight to be gained from our universe is as infinite as the universe itself, our comprehension is unfortunately finite.

Although the extraction of a net momentum has been postulated in inhomogeneous vacuums [35] (due to a different mechanism than that discussed in this paper), the effect was found to immeasurably small, and it remains unclear whether this small non-zero value is an artefact of the field regularization techniques used.Regardless though, if a continuous net force is indeed being produced in the experiments in Refs. [38–41], one might expect that this should also imply an anomalously high power loss from the electric circuits of the thruster device. This power loss would be in addition to any standard power losses associated with such things as: ohmic heating, eddy current losses, dielectric and ferrite heating, radiation losses, etc. Consequently, a dedicated effort to isolate known power losses from the total input power of the device should identify any additional anomalous losses.

Note: curiously the paper places the above-mentioned references 38 through 41 all under the same bracket (literally) but they are different models, some of them not even referring to the Quantum Vacuum (supposedly the subject of the paper: "Can the quantum vacuum be used as a reaction medium to generate thrust"):